1. Field of the Invention
The present invention generally relates to eye tracking, and more particularly to a dual mode eye tracking system and method.
2. Description of Related Art
Eye tracking is a technique of measuring gaze position of eyes by using sensors. Eye tracking devices (or eye trackers) may be classified into remote type and mobile type according to their configuration. As distance between a remote eye tracking device and eyes is at least tens of centimeters, the remote eye tracking device possesses low accuracy. A mobile eye tracking device is disposed near eyes (e.g., disposed at glasses) and thus has high accuracy. There are limits on usage time (e.g., a couple of hours) of the eye tracking device as power source needs be continuously turned on while performing tracking.
The eye tracking device may be adaptable to a variety of applications such as healthcare for preventing dry eye syndrome by detecting eye blinking. The eye tracking device may be adaptable to driving safety for preventing fatigue driving by analyzing driving concentration. The eye tracking device may be adaptable to virtual reality (VR) or augmented reality (AR) for achieving better performance by collecting auxiliary information.
Conventional eye tracking devices use one or more near-infrared light sources for capturing and analyzing infrared (IR) images to obtain gaze position of eyes. However, IR system causes erroneous judgment in outdoor with strong sunshine, thus reducing tracking accuracy. Therefore, conventional eye tracking devices are suitable for indoor applications.
More importantly, the IR light source of the mobile eye tracking device is near the eyes, which is exposed to IR light. Users ordinarily worry about injury to the eyes caused by IR light, and therefore users have no inclination to wear the mobile eye tracking device.
A need has thus arisen to propose a novel eye tracking scheme for reducing power consumption to lengthen usage time and for reducing the amount of IR light irradiating the eyes.